The great thing about this dish is you can make it the day before and pop it in the oven 10 minutes before you are ready for dinner.
I started by cooking down a couple spins of EVOO with about 6 cups of washed spinach and some salt. I like to use coarse Kosher salt.
When the spinach wilted down, I tossed it into a colander and pressed out as much of the water as possible. Then I coarsely chopped it.
In a medium pot I cooked a teaspoon of EVOO with 1 medium yellow onion (chopped), a clove of minced garlic (I use jarred), and salt and pepper. When the onion was soft, I added 1/4 cup of white wine (I always have some on hand. I don't think it matters what kind you use. Jack and I like our wine very sweet so we always have Reislings, Moscatos, or Gewurtztraminers on hand). When the wine was just about evaporated, I added 2 Tbsp of whole wheat flour and cooked it for about 30 seconds while whisking. I continued to whisk in 1.5 cups of half and half and a 1/2 tsp of fresh lemon juice. I brought this mixture to a boil over high.
While I was waiting for that to boil, I tore up 2 cups of whole wheat bread into bite-sized chunks and combined it in a bowl with a tablespoon of EVOO and a toss of salt.